closer-wise, eric gagne has the potential to be as good, if not better than mariano rivera.
in his first 3 seasons as a closer, gagne's accumulated 152 saves (rivera had 124 in his first 3).
its not easy to narrow down the best pitcher of all time.
nolan ryan, for example was overpowering and threw 7 no-hitters.
but he also walked a high number of batters, and finished his career a mere 32 games over .500...
koufax only pitched for 10 years, so his career stats pale next to pitchers who had longer careers...
will have to think about this some more